Zhaofen Lin

The Effect of Rhubarb Pre-Treatment on Intestinal Microcirculation in Septic Rats

The intestine plays a vital role in the pathophysiology of sepsis development. The objective of the present study was to explore the effects of rhubarb on intestinal microcirculation in septic rats. We used moorFLPI laser speckle imaging to detect the blood flow of the intestinal mucosa and wall. Using an ELISA, we assayed the concentration of lactate (L) and pyruvic acid (P) in the intestinal tissue to calculate the ratio of lactate to pyruvic acid (L/P ratio). To observe the intestinal mucosal capillaries, gelatin and ink were perfused into the intestine and subsequently stained with hematoxylin and eosin (HE) to measure the ratio of the vessel area. We then used immunohistochemistry to measure CD31 expression. Using an MTT assay, the effect of the rhubarb extract on the proliferation of human umbilical vein endothelial cells (HUVECs) was analyzed. The blood flow in the intestinal wall and mucosa of the control, sham and rhubarb-treated groups was significantly higher, while the sepsis group had relatively low blood flow. The L/P ratio in the intestinal tissue was larger in the sepsis group than in the other three groups. The microvascular area (MVA) in the sepsis group was smaller than in the control group, sham group or rhubarb group. Positive expression for CD31 was observed in the cytoplasm of vascular endothelial cells. The intestinal mucosal capillaries were reduced in septic rats as compared to the other three groups. HUVEC proliferation was enhanced by the rhubarb extract monomers at 1 μmol/L, but suppressed at higher concentrations of 10 to 100 μmol/L. These results suggest that pre-treatment with rhubarb prior to sepsis induction promotes the expansion of the intestinal mucosal capillaries, protects intestinal mucosal capillary endothelial cells and increases the number of functional intestinal capillaries.

Severe Sepsis Facilitates Intestinal Colonization by Extended-Spectrum-β-Lactamase-Producing Klebsiella pneumoniae and Transfer of the SHV-18 Resistance Gene to Escherichia coli during Antimicrobial Treatment

ABSTRACT Infections caused by multidrug-resistant pathogens are frequent and life threatening in critically ill patients. To investigate whether severe sepsis affects gut colonization by resistant pathogens and genetic exchange between opportunistic pathogens, we tested the intestinal-colonization ability of an extended-spectrum beta-lactamase-producing Klebsiella pneumoniae strain carrying the SHV-18 resistance gene and the transfer ability of the resistance gene to endogenous Escherichia coli under ceftriaxone treatment in rats with burn injury only or severe sepsis induced by burns plus endotoxin exposure. Without ceftriaxone treatment, the K. pneumoniae strain colonized the intestine in both septic and burned rats for a short time, with clearance occurring earlier in burn-only rats but never in sham burn rats. In both burned and septic rats, the colonization level of the challenge strain dropped at the beginning and then later increased during ceftriaxone treatment, after which it declined gradually. This pattern coincided with the change in resistance of K. pneumoniae to ceftriaxone during and after ceftriaxone treatment. Compared with burn-only injury, severe sepsis had a more significant effect on the change in antimicrobial resistance to ceftriaxone. Only in septic rats was the resistance gene successfully transferred from the challenge strain to endogenous E. coli during ceftriaxone treatment; the gene persisted for at least 4 weeks after ceftriaxone treatment. We concluded that severe sepsis can facilitate intestinal colonization by an exogenous resistant pathogen and the transfer of the resistance gene to a potential endogenous pathogen during antimicrobial treatment.

CRISPLD2 Is Expressed at Low Levels during Septic Shock and Is Associated with Procalcitonin

Introduction Previous studies have shown that cysteine-rich secretory protein containing LCCL domain 2 (CRISPLD2) is a novel lipopolysaccharide (LPS)-binding protein, and the upregulation of CRISPLD2 expression protects mice against LPS-induced lethality. The aim of this study was to examine the expression of CRISPLD2 in patients with sepsis and characterize the association of this protein with procalcitonin. Methods The expression of CRISPLD2 was determined in100 healthy volunteers and 119 septic patients. According to the definition of sepsis, patients were divided into three groups sepsis, severe sepsis, and septic shock. The relationship between CRISPLD2 levels and procalcitonin was also examined and statistically analyzed. Results The CRISPLD2 levels in healthy individuals were 219.3±69.1 µg/ml. Patients with sepsis exhibited higher CRISPLD2 levels than observed in healthy individuals (p = 0.001), but CRISPLD2 expression was not upregulated in patients with septic shock. No significant differences were observed between the levels of CRISPLD2 in surviving and non-surviving spesis patients. CRISPLD2 levels were negatively correlated with procalcitonin levels(r = −0.334, p<0.001). Conclusions The present study is the first to demonstrate the decreased expression of CRISPLD2 in septic shock and its association with PCT in sepsis. Further studies are needed to clarify the potential association between CRISPLD2 expression and clinical outcomes to determine if it could be used as a novel sepsis biomarker.

Changes of lymph metabolites in a rat model of sepsis induced by cecal ligation and puncture.

BACKGROUND Sepsis is a clinical syndrome defined by a systemic response to infection and remains a prevalent clinical challenge. The underlying pathophysiology of sepsis is poorly understood. Using a metabolomic method, the present study observed changes in lymph composition during sepsis in a septic model in an attempt to find out new biomarkers for the early diagnosis and treatment of sepsis. METHODS Adult male Sprague-Dawley rats underwent cecal ligation and puncture. Blood samples were obtained via the lateral caudal vein, and lymph was obtained from the thoracic duct. Cytokines were measured in plasma and lymph samples by enzyme-linked immunosorbent assay at different time points after cecal ligation and puncture. Rat lymph samples were analyzed by high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. Multivariate analysis was used to profile potential biomarkers in rat septic lymph samples. RESULTS Plasma and lymph tumor necrosis factor &agr;, interleukin 1&bgr;, and interleukin 6 levels were elevated in septic group as compared with the control. Of the 10 characteristic metabolites identified in the septic model, six (palmitoyl-L-carnitine, creatinine, phenylalanine, isonicotinic acid, choline, and 5-azacytidine) were high, and four (1-O-Hexadecyl-2-lyso-glycero-3-phosphorylcholine, alanine, 4-amino-5-hydroxymethyl-2-methylpyrimidine, and asymmetric dimethylarginine) were low. CONCLUSION These biomarkers were mainly involved in energy metabolism and vascular tone and may prove beneficial to distinguish sepsis from other inflammatory conditions or predict outcomes.

Targeting programmed cell death 4 (PDCD4) with biogenic compounds in ARDS by Gaussian process‐based QSAR virtual screening

The programmed cell death 4 (PDCD4) has recently been recognized as a new and attractive target of acute respiratory distress syndrome. Here, we attempted to discover new and potent PDCD4 mediator ligands from biogenic compounds using a synthetic strategy of statistical virtual screening and experimental affinity assay. In the procedure, a Gaussian process‐based quantitative structure‐activity relationship regression predictor was developed and validated statistically based on a curated panel of structure‐based protein‐ligand affinity data. The predictor was integrated with pharmacokinetics analysis, chemical redundancy reduction, and flexible molecular docking to perform high‐throughput virtual screening against a distinct library of chemically diverse, drug‐like biogenic compounds. Consequently, 6 hits with top scores were selected, and their binding affinities to the recumbent protein of human PDCD4 were identified, 3 out of which were determined to have high or moderate affinity with Kd at micromolar level. Structural analysis of protein‐ligand complexes revealed that hydrophobic interactions and van der Waals contacts are the primary chemical forces to stabilize the complex architecture of PDCD4 with these mediator ligands, while few hydrogen bonds, salt bridges, and/or π‐π stacking at the complex interfaces confer selectivity and specificity for the protein‐ligand recognition. It is suggested that the statistical Gaussian process‐based quantitative structure‐activity relationship screening strategy can be successfully applied to rational discovery of biologically active compounds. The newly identified molecular entities targeting PDCD4 are considered as promising lead scaffolds to develop novel chemical therapeutics for acute respiratory distress syndrome.

NF-κB-Induced MicroRNA-211 Inhibits Interleukin-10 in Macrophages of Rats with Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome

Background/Aims: The present study addressed the potential involvement of microRNAs in acute respiratory distress syndrome (ARDS)-related inflammation and elucidates the underlying molecular mechanism. Methods: ARDS rat model was established by lipopolysaccharide, with compromised gas exchange capacity and lung edema. The inflammatory cells from bronchoalveolar lavage fluid (BALF) were profiled with automatic blood cell analyzer. The relative fluorescence intensity of BALF-derived macrophages was analyzed by flow cytometry. The relative microRNA expression was determined using microarray and Taqman assay. The secretory interleukin (IL)-10 was measured by enzyme-linked immunosorbent assay. Luciferase reporter assay was performed to determine the regulatory effects of miR-211 and NF-κB on IL-10 and miR-211 expressions, respectively. Chromatin immunoprecipitation (ChIP) was conducted to detect the direct binding of NK-κB on miR-211 promoter. The protein level was determined by Western blot. Results: The provoked acute inflammation was characterized with increased total cells, macrophages, neutrophils and lymphocytes. The relative expression of miR-211 was aberrantly up-regulated in BALF-derived macrophages from ARDS rats, which was accompanied with reduction of secretory IL-10. We further demonstrated that miR-211 inhibited IL-10 expression by binding to its 3’-UTR. The expression of miR-211 was modulated by NF-κB. Conclusion: Here we elucidated a crucial role of NF-κB/miR-211/IL-10 signaling axis in ARDS-related inflammation.

Comparative Study of Plasma Endotoxin with Procalcitonin Levels in Diagnosis of Bacteremia in Intensive Care Unit Patients

Background:Both procalcitonin (PCT) and plasma endotoxin levels cannot be solely used for a definite diagnosis of bacteremia or sepsis, and there has been few study comparing the values of the two biomarkers for the diagnosis of bacteremia. The aim of this study was to identify bacteria causing bacteremia and evaluate the role of the two biomarkers in the diagnosis of bacteremia in Intensive Care Unit (ICU). Methods:The medical records of 420 patients in ICU were retrospectively reviewed. Patients (n = 241) who met the inclusion criteria were subjected to blood culture (BC) for the analysis of the endotoxin or PCT levels. The exclusion criteria included the presence of infection with human immunodeficiency virus and/or AIDS, neutropenia without sepsis, pregnancy, treatment with immunosuppressive therapies, or blood diseases such as hematological tumors. Patients’ BC episodes were divided into BC negative, Gram-negative (GN) bacteria, Gram-positive bacteria, and fungi groups. The PCT and plasma endotoxin levels were compared in the different groups. Results:A total of 241 patients with 505 episodes of BC were analyzed. The GN bacteria group showed higher levels of PCT and endotoxin than the BC negative, Gram-positive bacteria, and fungi groups. GN bacteremia was more prevalent than Gram-positive bacteremia. The GN bacteremia caused by non-Enterobacteriaceae infection presented higher endotoxin level than that by Enterobacteriaceae, but no significant difference in PCT levels was observed between the two groups. The plasma endotoxin significantly differed among different groups and was bacterial species dependent. Conclusions:Plasma endotoxin was more related to GN than to Gram-positive bacteremia, and that endotoxin level was species dependent, but PCT level remained relatively more stable within the GN bacteria caused bacteremia. Both GN and positive bacteria caused bacteremia in the ICU patients in different regions of China. And PCT is a more valuable biomarker than endotoxin in the diagnosis of bacteremia.

Rhubarb Monomers Protect Intestinal Mucosal Barrier in Sepsis via Junction Proteins.

Background: Leakage of the intestinal mucosal barrier may cause translocation of bacteria, then leading to multiorgan failure. This study hypothesized that rhubarb monomers might protect the gut mucosal barrier in sepsis through junction proteins. Methods: Healthy male Sprague-Dawley rats (weighing 230–250 g) under anesthesia and sedation were subjected to cecal ligation and perforation (CLP). After surgical preparation, rats were randomly assigned to eight groups (n = 6 or 8 each group): sham group (Group A: normal saline gavage); sepsis group (Group B: normal saline gavage); Group C (intraperitoneally, dexamethasone 0.5 mg/kg) immediately after CLP surgery; and rhubarb monomer (100 mg/kg in normal saline)-treated groups (Group D: rhein; Group E: emodin; Group F: 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid; Group G: 1-O-caffeoyl-2-(4-hydroxy-O-cinnamoyl)-D-glucose; and Group H: daucosterol linoleate). Animals were sacrificed after 24 h. Intestinal histology, lactulose, mannitol concentrations were measured, and zonula occludens (ZO)-1, occludin and claudin-5 transcription (polymerase chain reaction), translation (by Western blot analysis), and expression (by immunohistochemistry) were also measured. Results: Intestinal histology revealed injury to intestinal mucosal villi induced by sepsis in Group B, compared with Group A. Compared with Group A (0.17 ± 0.41), the pathological scores in Groups B (2.83 ± 0.41, P < 0.001), C (1.83 ± 0.41, P < 0.001), D (2.00 ± 0.63, P < 0.001), E (1.83 ± 0.41, P < 0.001), F (1.83 ± 0.75, P < 0.001), G (2.17 ± 0.41, P < 0.001), and H (1.83 ± 0.41, P < 0.001) were significantly increased. Lactulose/mannitol (L/M) ratio in Group B (0.046 ± 0.003) was significantly higher than in Group A (0.013 ± 0.001, P < 0.001) while L/M ratios in Groups C (0.028 ± 0.002, P < 0.001), D (0.029 ± 0.003, P < 0.001), E (0.026 ± 0.003, P < 0.001), F (0.027 ± 0.003, P < 0.001), G (0.030 ± 0.005, P < 0.001), and H (0.026 ± 0.002, P < 0.001) were significantly lower than that in Group B. ZO-1, occludin and claudin-5 transcription, translation, and expression in Group B were significantly lower than that in Group A (P < 0.001), but they were significantly higher in Groups C, D, E, F, G, and H than those in Group B (P < 0.05). Conclusion: Rhubarb monomer treatment ameliorated mucosal damage in sepsis via enhanced transcription, translation, and expression of junction proteins.

Rhubarb Antagonizes Matrix Metalloproteinase-9-induced Vascular Endothelial Permeability

Background:Intact endothelial structure and function are critical for maintaining microcirculatory homeostasis. Dysfunction of the latter is an underlying cause of various organ pathologies. In a previous study, we showed that rhubarb, a traditional Chinese medicine, protected intestinal mucosal microvascular endothelial cells in rats with metastasizing septicemia. In this study, we investigated the effects and mechanisms of rhubarb on matrix metalloproteinase-9 (MMP9)-induced vascular endothelial (VE) permeability. Methods:Rhubarb monomers were extracted and purified by a series of chromatography approaches. The identity of these monomers was analyzed by hydrogen-1 nuclear magnetic resonance (NMR), carbon-13 NMR, and distortionless enhancement by polarization transfer magnetic resonance spectroscopy. We established a human umbilical vein endothelial cell (HUVEC) monolayer on a Transwell insert. We measured the HUVEC permeability, proliferation, and the secretion of VE-cadherin into culture medium using fluorescein isothiocyanate-dextran assay, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, and enzyme-linked immunosorbent assay, respectively, in response to treatment with MMP9 and/or rhubarb monomers. Results:A total of 21 rhubarb monomers were extracted and identified. MMP9 significantly increased the permeability of the HUVEC monolayer, which was significantly reduced by five individual rhubarb monomer (emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl)-&bgr;-D-glucose, daucosterol linoleate, and rhein) or a combination of all five monomers (1 &mgr;mol/L for each monomer). Mechanistically, the five-monomer mixture at 1 &mgr;mol/L promoted HUVEC proliferation. In addition, MMP9 stimulated the secretion of VE-cadherin into the culture medium, which was significantly inhibited by the five-monomer mixture. Conclusions:The rhubarb mixture of emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl)-&bgr;-D-glucose, daucosterol linoleate, and rhein, at a low concentration, antagonized the MMP9-induced HUVEC monolayer permeability by promoting HUVEC proliferation and reducing extracellular VE-cadherin concentrations.